diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index eef02d1..147b542 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -567,10 +567,10 @@ impl QrCode {
 		// Interleave (not concatenate) the bytes from every block into a single sequence
 		let mut result = Vec::<u8>::with_capacity(rawcodewords);
 		for i in 0 .. shortblocklen + 1 {
-			for j in 0 .. numblocks {
+			for (j, block) in blocks.iter().enumerate() {
 				// Skip the padding byte in short blocks
 				if i != shortblocklen - blockecclen || j >= numshortblocks {
-					result.push(blocks[j][i]);
+					result.push(block[i]);
 				}
 			}
 		}
diff --git a/typescript-javascript/qrcodegen.ts b/typescript-javascript/qrcodegen.ts
index a7f0ab4..00e7827 100644
--- a/typescript-javascript/qrcodegen.ts
+++ b/typescript-javascript/qrcodegen.ts
@@ -435,11 +435,11 @@ namespace qrcodegen {
 			// Interleave (not concatenate) the bytes from every block into a single sequence
 			let result: Array<byte> = [];
 			for (let i = 0; i < blocks[0].length; i++) {
-				for (let j = 0; j < blocks.length; j++) {
+				blocks.forEach((block, j) => {
 					// Skip the padding byte in short blocks
 					if (i != shortBlockLen - blockEccLen || j >= numShortBlocks)
-						result.push(blocks[j][i]);
-				}
+						result.push(block[i]);
+				});
 			}
 			if (result.length != rawCodewords)
 				throw "Assertion error";